#include <stdio.h>
#include <assert.h>
char* my_strcpy(char* a, const char* b)
{
	assert(a && b);
	char* ret = a;
	while (*a++ = *b++)
		;
	return ret;
}

int main()
{
	char a[] = "abcdef";
	char b[20] = { 0 };
	my_strcpy(b, a);
	printf("%s\n", b);
	return 0;
}